Who's competent, and how do you know?

People who lack the knowledge or wisdom to perform well are often unaware of this fact. That is, the same incompetence that leads them to make wrong choices also deprives them of the savvy necessary to recognize competence, be it their own or anyone else's.

It's worth reading the whole article in Salon.

Another money quote:

In short, smart people tend to believe [wrongly, according to context ~ N.] that everyone else "gets it." Incompetent people display both an increasing tendency to overestimate their cognitive abilities and a belief that they are smarter than the majority of those demonstrably sharper.